An electrical feedthrough can be used in an implantable medical device (IMD) to provide an isolated electrical circuit path from the exterior of the IMD to an interior of a housing. Feedthroughs can be used with housings that are sealed, such as a biocompatible hermetically sealed housing. The electrical path can provide an electrical connection to components inside the housing from outside the housing. To preserve internal components, the feedthrough can be leak-resistant. Some feedthrough designs are biocompatible and hermetically sealed. Some implantable medical devices using such a hermetically sealed housing can protect implanted electronics from body fluids and can resist undesirable exposure of the patient to materials from inside the housing.
To provide such a feedthrough, a ferrule, or mechanical element can be disposed through the housing and coupled to the housing. An electrical conductor can extend through the ferrule. A seal and/or electrical insulator can be disposed between the ferrule and the conductor. A hermetically sealed ferrule configured as such can maintain hermeticity of the case while allowing an electrical signal to enter the case.
A feedthrough connector for an implantable medical device is discussed in U.S. Pat. No. 4,934,366 entitled, “Feedthrough Connector for an Implantable Medical Device.” An implantable connector that electrically connects multi-conductor leads to an implantable medical device is discussed in U.S. Pat. No. 7,736,191 entitled, “Implantable Connector with Protected Contacts.”
A hermetic implantable medical device is discussed in U.S. Patent No. US 2,006,247,714 entitled, “Glass-to-metal Feedthrough Seals Having Improved Durability Particularly Under AC or DC Bias.”
An optical window assembly for use in implantable medical device is discussed in U.S. Pat. No. 5,902,326 entitled, “Optical Window for Implantable Medical Devices.”
These approaches have a number of shortcomings, including, but not limited to, complexity, difficulty to manufacture, and high cost.